Self-cleaning port



Oct. 18, 1927. 1,645,700

w. B. HoDGE:

SELF CLEANNG PORT Original Filed May 19. 19215 v Pateniea oct. 18,1927..

VUNITED STATES PATENT OFFICE.

WILLIAM B. HODGE, OF CHARLOTTE, NORTH CAROLINA, ASSIGNOR TOPARKS-GRANIER COMPANY, OF FITCHBURG, MASSACHUSETTS, A CORPORATION OFMASSACHUSETTS.

SELF-CLEANIN G PORT.

Original application filed May 19, 1923, Serial No. 640,283. Divided andthis application led September 9, 1924. Serial No. 736,802.

This invention relates to cleaning devlces for the throttling feed portsof pneumatic devices, and rovides a mechanism intended particularly oruse in pneumatic relay motors such as are used in' temperature andhumidity controlling systems.

The presentapplication is a division of a prior application, VSerial No.640,283, filed May v19, 1923.

Generally stated the'invention contemplates the use of a motor, subjectto the' pressure of t-he air supply, and rendered operative to clean thefeed port by a reduction of supply pressure, caused for the purpose, or

5 as an incident to shuttingdown the system.

The relay motors used in temperature and humidity ,regulating systemscommonly 1nclude a diaphragm chamber having a leak' port controlled by athermostatic or hygrostatic valve. When the system is in operation airunder pressure is constantly fed to the diaphragm chamber through athrottling feed port whose capacity is less than that of the leak port.Thus the closing and opening of the leak port by the thermostat-ic orhygrostatic valve ycauses the alternate distention and collapse of thediaphragm.

Such throttling feed ports being quite minute are apt to become cloggedwith `dust and scale, and the present invention provides means forcleaning such ports each time the supply pressure is materially reduced,as it is, for example, when the system is shut down. v

`The application of the invention to a known type of relay motor used intemperature and humidity regulation is illustrated inl the accompanyingdrawing, in which t- Fig. 1 is a section showing the main operativepart-s ofthe motor.

Fig. 2 is a fragmentary section showing the feed port opened and itscontact with the wiper when the air supply is shut oil".

The diaphragm motor above referred to consists of a corrugated metalbellows 6, closedE at one end by a fixed head 7 and at the other by amovable head 8. A spring 9 acts against. the head 8, tending to collapsethe diaphragm, but the range of collapsing movement is limited by aliange 10 formed on head 8.

The head 8 is further provided with a projecting stud 11 which abutsagainst a valve stem 12. This valve stem 12 passes through Ithrustrelation with each other. The stem l of the exhaust valve 20 has anaxial recess in which the end of the inlet valve stem seats and isguided, and a spring 21 which ,bears against the inlet valve, serves toclose the latter and open the exhaust. Th space above exhaust valve 20is connected o atmosphere by a pipe 22 which directs the exhausted airto a point of use disclosed in the parent application but not materialto the present invention. The space below inlet valve 19 is connected bypassage 23 to the compressed air supply pipe 24:.

The branch pipe 25 is for a purpose disclosed in the parent applicationand not material' to the present application, since it merely suppliesair under pressure to certain accessory apparatus.

The pressure fluid within diaphragm 6 is confined and vented alternatelyby the openlng and closing of a familiar type 'of leak portto which thepipe 26 leads. One embodiment ofthe port with its controlling v alve isillustrated in .the parent applicat1on, but since it is not material tothe present invention it is here omitted.

To operate a motor of the above described type air must be suppliedconstantly to the iaphragm chamber at a rate less than the outflowcapacity of the lea-k port, by the use of a restricted feed port.According to the present invention I form this port on the side of amovable valve-like member 27, the port consisting of a groove 28.

The member 27 is supported on a stem 29 which 1s fixed on a head 30,While the head 3() 1s carried by a metallic bellows diaphragm 31. Thecompressed air supply pipe 24 communicates with the interior of bellows31 so that when the supply pressure is 011, the valve-like member 27 isdrawn down intoa seat 32, formed to receive it. ln this position thegroove 28 offers the only path past the member 27.

TVhen the supply pressure is materially reduced or shut 'oft' a spring33 acting ward movement of rod 29 is limited by a flan e 36 withinbellows 3l.

T us whenever the system is shut down, the feed groove will beeffectively cleaned. Since most such systems are shut down at night theinvention provides cleaning at least once each twenty-four hours.

What is claimed is:

1. IThe combination with a'pressure fluid actuated control device of therelay motor type requiring a restricted port, which serves as a feedport for said relay motor of a valve like member and a seat therefor,one of which is formed'at its seating area with a groove arranged toserve, when the two are in contact, assaid restricted port; and meansincluding an abutment subject to supply pressure Vand arranged to seatsaid valve like member in'said seat when supply pres sure is active, andto separate the two at other times. f

2. The combination with a pressure fluid actuated control device of thetype requiring a restricted port, of a conical seat memberg. a conicalvalve-like member adapted to 'pas seat therein and having a channel inits conical fact adapted to serve, when the valvelike member is seated,as said restricted port; means including an abutment subject to supplypressure, and arranged to seat said valve-like member in said .seatfwhen supply pressure is active and to separate the two at other times;and a wiper resiliently mounted in position to wipe said groove as thevalve moves nearits fully separated position.

3. The combination with an automatic control device of the pressurefluid actuated type, including a restricted port formed between tworelatively movable members; an \abutment subject to the pressure ofpressure fluid supply in one direction and connected to produce movementof said members upon ing means acting on said abutment in oppo y'-sitionto said supply pressure. j

5. The combination with an automatic control device'of the relay motortype, of a seat; a head adapted to sealv against said seat and having agroove on its seating face which serves as a restricted feed port forpressure fluid to said control device; an abutment subject to thepressure of fluid supplyl and connected with said head to move the sameupon changes of pressure of mo- -tive Huid supply; a wiper mounted in apo-V sition to engage said head and the groove therein as the headrmoves away from said seat; and resilient means urging said abutment inopposition to said fluid pressure.

In testimony whereof I have'signed my name to thisspecification.

, W'ILLIAM B. HODGE.

Yso

